At least 14 people were killed and several others wounded on Friday when a suicide bomber detonated himself inside a Shiite mosque in the Afghanistan capital of Kabul, according to Reuters. As per an Associated Press report, a member of Afghanistan’s Shiite clerical council confirmed the deaths in the attack that is still underway. As the siege continued, more loud explosions have been heard. Security forces have been unable to advance fearing even greater casualties. Meanwhile, a second explosion was reported from near the Imam Zaman mosque.

According to initial reports, the cleric who performed the prayer service has been killed, as well as a security guard outside the mosque in a northern Kabul neighborhood on Friday. Mir Hussain Nasiri says gunmen have taken over the portion of the mosque with the separate prayer areas for men and women.

The Interior Ministry spokesman Najib Danish confirmed a “terrorist attack” had taken place and one of the attackers blew himself up outside Imam Zaman Mosque in PD11. The attack occurred as worshipers gathered for afternoon prayers on the Islamic holy day of Friday.

Kabul Police officials said the blast was followed by gunfire. Witnesses told news agency Reuters that the gunmen threw grenades before entering the mosque. The police further added the attack had caused some casualties and they were preparing to try to clear the mosque.

There was no immediate claim of responsibility, but Islamic State militants have attacked Shiite Muslim targets in Afghanistan in the past.